Shotshell base wad



Dec. 26, 1967 G. l.. HERTER 3,359,906

SHOTSHELL BASE WAD Filed DSG. 20, 1965 INVENTOR.

A waal/e745 United States Patent O 3,359,906 SHOTSHELL BASE WAD GeorgeL. Herter, Waseca, Minn., assignor to Herters Inc., Waseca, Minn., acorporation of Minnesota Filed Dec. 20, 1965, Ser. No. 514,935 2 Claims.(Cl. 102-95) ABSTRACT F THE DISCLOSURE A base wad for use with ashotshell including a generally cylindrical body formed of a plasticmaterial having a concave front end to receive the powder charge thereinand having a base end with a radially extending flange projectingoutwardly therefrom and defining a cushioning pocket between the baseand shotshell head. A primer pocket in the body extending axially fromthe base end and a smaller opening extending axially from the front endand communicating with the primer pocket to define a shoulder overlyingthe primer cap positioned in the primer pocket. A plurality of sealingand cushioning elements integrally formed with the body and projectingradially outwardly therefrom throughout the length thereof engaging theinner circumferential surface of the shotshell to form a seal thereatand to produce a cushioning effect when the base wad is subjected topressure forces produced by a detonated propellant charge.

This invention relates to firearm cartridges and more particularlyrelates to an improved base wad for shotshells.

In the construction of shotshells it is desirable to use a base Wadinside the head of the shotshell to keep the powder or propellant chargedisposed in front of the flashing end of the primer as well as to holdthe primer cap to the brass base and prevent gas from leaking out of theprimer hole or base at detonation. Several methods have been attemptedto properly carry out this function. Several types of base wads havebeen tried including a hollow plastic base wad lled with paper. Thisconstruction was not successful in that gases escaped into the primercap area upon detonation. This results in greatly reduced efficiency inthe use of the propellant charge. Paper base wads have been successfulto some extent. However, all of the wads known to date have presentedthe problem of not properly sealing the gases generated by the explosionof the propellant charge within the propellant charge chamber. The gasesmust be sealed from expanding either into the shot cup area, therebydestroying the pattern pof the shot, or from expanding into the primercap area, thereby decreasing the eiciency of the propellant charge.Gases which escape into the shotshell head may also destroy or distortthe head of the shell, preventing its reuse by hand loaders.

With these comments in mind it is to the elimination of these and otherdisadvantages to which the present invention is directed along with theinclusion therein of other novel and desirable features.

An object of my invention is to provide a new and mproved base wad ofsimple and inexpensive construction and operation.

Another object of my invention is the provision of a base wad whichseals gases from the head of the shotshell case and from the primer caparea.

Another object of my invention is the provision of a base wad which,upon detonation of the propellant charge, maintains a seal withoutdistorting the head of the shotshell and without cracking -or otherwisedeforming the base wad.

A still further object of my invention is the provision of a base wadwhich disposes the powder or propellant charge properly within thepropellant charge chamber in front of the primer cap while allowing theproper amount of primer flash to escape from the flashing end of theprimer cap into the propellant charge.

These and other objects and advantages of -rny invention will more fullyappear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views and in which:

FIG. 1 is a partial longitudinal sectional View taken along a planethrough the center of the shotshell.

FIG. 2 is a partial longitudinal sectional view taken along a planethroughout the center of the shotshell at the precise time ofdetonation.

FIG. 3 is a perspective view showing the base wad of -my invention as itappears separate from the shotshell,

FIG. 4 is an elevation of the base wad of my invention with a breakawayportion showing the primer pocket sealing and cushioning elements.

FIG. 5 is a longitudinal sectional view taken along a plane through thecenter of the shotshell showing an alternate construction of my base wadand an alternate as sembly of the base wad and shotshell.

FIG. 6 is a partial perspective view showing an alternate base wad withsealing and cushioning elements projecting downwardly from the powderengaging surface.

FIG. 7 is a partial perspective view showing an alternate base Wad withsealing and cushioning elements projecting outwardly.

FIG. 8 is a partial longitudinal sectional view taken along a planethrough the center of the base wad and showing sealing and cushioningelements directed downwardly into the primer pocket.

FIG. 9 is a partial longitudinal sectional View taken along a planethrough the center of the base wad and showing sealing and cushioningelements directed upwardly into the primer pocket.

The base wad of my invention is shown in FIG. 1 and is indicated ingeneral by numeral 10. Ba-se wad 10 is of molded construction and formedfrom compressible resilient plastic material such as polyethylene.Considerably harder plastic formulations may also be utilized to achieveoptimum operating characteristics or Variations in performance. The basewad is shown assembled in a generally tubular plastic or paper shotshellengaging the casing side wall 11a of the shotshell 11. A tubular brasshead 12 is shown surrounding the shotshell and includes a brass base 13generally circular in shape and having a recessed area 14 to receive aprimer cap 15. The primer cap is inserted axially into the recess 14 andthrough aperture 15b in the base 13. The shotshell includes a baseportion 16 in contact with the base portion 13 of the brass head 12 andincludes an aperture 17 in registry with the recess 14 and aperture 15bof the base 13 of the brass 3 head 12. The primer cap is inserted withthe flashing end 17a forward toward the propellant charge or powder 17b.Any of the conventional over-powder wads may be disposed above thepowder 17b to define and seal the propellant or powder chamber.

Referring to FIG. l, base wad 10 includes a lower, substantially annularfiange or skirt portion 18 which projects downwardly and contacts theinside surface of the shotshell case 11. Flange 18 defines a cushioningrecess between the base 16 of the casing and the lower transversesurface of the base wad 10. An axial primer pocket 20 is included in thebase wad and is adapted to receive the primer cap 15. Axially spaced,substantially annular inner sealing and cushioning elements 21 engagethe primer cap 15 providing a seal thereto. Aperture 22 communicateswith the primer cap 15 at the flashing end 17b thereof, disposing powder17b at the ashing end of the primer cap 15. A transverse annularshoulder 23 engages the primer cap 15 at the ashing end thereof andeffects a seal therebetween. Substantially annular, radially projecting,axially spaced sealing and cushioning elements or convolutions 24 areincluded on the outer periphery of the base wad 10. The sealing andcushioning elements 24 engage the side walls 11a of the case providing aseal thereto. The sealing and cushioning elements have a saw-toothcross-section with the teeth extending generally upwardly toward thepropellant charge 17b. The teeth are typically reslient and yieldable,springing back into position after detonation.

The upper portion of the base wad 10 includes radially projecting,axially spaced rings 24 surrounding a powder chamber 25 generallydefined by the concave walls extending from the top of the base waddownwardly to the aperture 22. The powder chamber encloses powder whichinterconnects the propellant charge 17b with the flashing end 17a of theprimer cap 15. Aperture 22 is of a diameter smaller than the diameter ofthe primer cap 15 yet large enough to permit the primer flash tocommunicate with the propellant charge 17 b, thereby detonating thepropellant charge, while continuously maintaining a seal at shoulder 23between the powder chamber and the primer pocket 20.

Referring to FIG. 3, flange 18 is shown projecting downwardly fromsurface 19. Aperture 17, which receives primer cap 15, is shown with oneof the sealing and cushioning elements 21. The outer sealing andcushioning elements 24 are indicated at 24. Referring to FIG. 4, thebreak-away view shows the opening for the primer cap 15 and shows thesealing and cushioning rings 21 which engage the primer cap 15. Upwardlyprojecting sealing and cushioning rings 24 engage the walls of theshotshell 11. Flange 18 is shown projecting downwardly defining thecushioning recess between the base wad and the shotshell.

The operation of the base wad of my invention is best described byreferring to FIG. 2. At the precise point of detonation, the base wad ofmy invention is placed under extreme pressure. In fact, the entireshotshell is placed under pressure from the explosive force of thepropellant charge which has been detonated by the primer cap. Thepressure forces the base wad 10 downwardly toward the base 13 of theshotshell. Since the teeth 24 project upwardly, the base wad may movedownwardly without difficulty and without destroying the seal. Thesealing and cushioning elements are also forced outwardly at the pointof detonation since the base wad is put under compression, increasingthe diameter of the wad. Since the sealing and cushioning elements arespaced axially, the seal is maintained between the casing and the basewad at the time of detonation with additional sealing obtained from theoutward force of the base wad on the shotshell casing. The sealing andcushioning elements are yieldable and resilient, absorbing the shockbetween the wad and casing and springing back into position afterdetonation. Rings 21 engage the primer cap maintainng a seal at thspoint. At detonation the diameter of the wad primer pocket is Caldecreased and the seal becomes tighter without distorting the wad sincethe rings 21 absorb the shock between the primer cap and the primerpocket. Additional sealing is effected at flange 23 from the tight fitbetween the cap 15 and the flange 23. When detonation takes place thepressure forces flange 23 downwardly into sealing engagement with thepriming cap 15. After the pressure has been absorbed the base wadsprings back into position since it has been cushioned from the adverseeffects of the explosion. The casing and base wad may now be reloadedsince there has been no adverse effect on them from firing.

An alternate embodiment of my invention is shown in FIG. 5. A plasticshotshell casing is indicated at numeral 26. A base wad 27 is shown withskirt or fiange 28 crimped to the rim of the brass head 29. This securesthe base wad to the shotshell casing, while maintaining the sealing andcushioning effect of the base wad of my invention. The primer cup 30fits snugly within the primer pocket 31, at detonation, the pressureexerted on the base wad are absorbed by the outer sealing in cushioningelements 32.

FIG. 6 shows an alternate base wad having sealing and cushioningelements or teeth 33 projecting downwardly from the powder engagingsurface 34, adapted to seal with the inside periphery of the shotshellcasing.

In FIG. 7, an alternate base wad is shown having sealing and cushioningrings 35 projecting outwardly from the powder engaging surface 36, toform a seal with the casing of the shotshell.

A partial sectional view of an alternate base wad is shown in FIG. 8 andshows internal sealing and cushioning convolutions or teeth 37 disposedat the primer cap 38. Sealing and cushioning convolutions 37, whichproject downwardly form a seal between the base wad and the primer cappreventing gases from escaping upon detonation of the shotshell.

Another embodiment of my invention is shown in FIG. 9 which showssealing and cushioning rings 39 disposed internally at the primer cap 40projecting upwardly toward the powder charge. Rings 39 form a sealbetween the primer cap and base wad and also tend to hold the primer capupwardly in position against the powder charge.

It will, of course, be understood that various changes may be made inthe form, details, arrangement and proportions of the various partswithout departing from the scope of my invention.

What is claimed is:

1. A base wad adapted to be seated within and corporate with the head ofa shotshell, said base wad comprismg:

a generally cylindrical plastic body having a base end and a concavefront end to receive a powder charge therein,

an annular fiange integral with said base end and projecting radiallyoutwardly and slightly axially therefrom and delining with said base enda concave cushioning pocket between the base end and shotshell head,

a primer in said body extending axially from said base end for receivinga primer cap therein,

said body having an opening therein extending axially from said concavefront end and communicating with said primer pocket, said opening beingof a substantially smaller cross-sectional size than said primer pocketto define an annular shoulder for overlying the end of a primer cap inthe primer pocket,

said body having a plurality of similar sealing and cushioning elementsintegrally formed therewith throughout the length thereof and projectingout. wardly from the exterior surface of said body and adapted to engagethe inner circumferential surface of the shotshell, each of saidelements being equally spaced apart and disposed in closely proximalrelation to each adjacent element to define a plurality of closelyspaced apart outwardly opening grooves of References Cited substantiallythe same size whereby said elements UNITED STATES PATENTS may be readllyurged towards each other to form a seal with the inner surface of theshotshell and to 97,537 12/1869 Logan 1oz-44 produce a cushioning effectthereat when the base 5 /Ionhamt--l dbtdt ayerea Wa 1s su )ec e opressure forces produced by a 3,246,603 4/1966 Comerford 1oz-42detonated propeller charge.

2. The base Wad as defined in claim 1, wherein said cushioning elementsand grooves extend outwardly and BENJAMIN A' BORCHELT Prlmmy Exbmmerupwardly. 10 ROBERT F. STAHL, Examiner.

1. A BASE WAD ADAPTED TO BE SEATED WITHIN AND CORPORATE WITH THE HEAD OFA SHOTSHELL, SAID BASE WAD COMPRISING: A GENERALLY CYLINDRICAL PLASTICBODY HAVING A BASE END AND A CONCAVE FRONT END TO RECEIVE A POWDERCHARGE THEREIN, AN ANNULAR FLANGE INTEGRAL WITH SAID BASE END ANDPROJECTING RADIALLY OUTWARDLY AND SLIGHTLY AXIALLY THEREFROM ANDDEFINING WITH SAD BASE END OF CONCAVE CUSHIONING POCKET BETWEEN THE BASEEND AND SHOTSHELL HEAD, A PRIMER IN SAID BODY EXTENDING AXIALLY FROMSAID BASE END FOR RECEIVING A PRIMER CAP THEREIN, SAID BODY HAVING ANOPENING THEREIN EXTENDING AXIALLY FROM SAID CONCAVE FRONT END ANDCOMMUNICATING WITH SAID PRIMER POCKET, SAID OPENING BEING OF ASUBSTANTIALLY SMALLER CROSS-SECTIONAL SIZE THAN SAID PRIMER POCKET TODEFINE AN ANNULAR SHOULDER FOR OVERLYING THE END OF A PRIMER CAP IN THEPRIMER POCKET, SAID BODY HAVING A PLURALITY OF SIMILAR SEALING ANDCUSHIONING ELEMENTS INTERALLY FORMED THEREWITH THROUGHOUT THE LENGTHTHEREOF AND PROJECTING OUTWARDLY FROM THE EXTERIOR SURFACE OF SAID BODYAND ADAPTED TO ENGAGE THE INNER CIRCUMFERENTIAL SURFACE OF THESHOTSHELL, EACH OF SAID ELEMENTS BEING EQUALLY SPACED APART AND DISPOSEDIN CLOSELY PROXIMAL RELATION TO EACH ADJACENT ELEMENT TO DEFINE APLURALITY OF CLOSELY SPACED APART OUTWARDLY OPENING GROOVES OFSUBSTANTIALLY THE SAME SIZE WHEREBY SAID ELEMENTS MAY BE READILY URGEDTOWARDS EACH OTHER TO FORM A SEAL WITH THE INNER SURFACE OF THESHOTSHELL AND TO PRODUCE A CUSHIONING EFFECT THEREAT WHEN THE BASE WADIS SUBJECTED TO PRESSURE FORCES PRODUCED BY A DETONATED PROPELLERCHARGE.